Time switch
by Robotech275
Summary: Sans hears about Toriel's tragic past and wants to help her. Will he be able to save the two children?
1. Chapter 1

_**dream1990 gave me this idea for a fan fiction. Enjoy. (Or don't and waste your time.)**_

Sans' pov.

I have visited Toriel today. It was like the other times. We shared jokes, told each other stories, Papyrus finding me and saying how lazy I am. Except Toriel seemed sad. When I asked her what was wrong she told me about failing to protect the fallen children as well as her own. That is how I found out about Chara. The first fallen human. And about death of the Prince. I wanted to help her but I couldn't do anything. Until today. I tried to repair the machine that was behind mine and Papyrus' house. If this worked then I could go into the past and change everything.

"BROTHER? WHERE ARE YOU, YOU LAZY SACK OF BONES GET BACK HERE."

I teleported behind Papyrus.

"hey bro. what has gotten you so rattled up?"

"WHY ARE YOU NOT AT YOUR POST? WHAT IF A HUMAN COMES BY? WE NEED TO BE READY."

"bro. there is something I need to tell you. this is not the first time you said that to me."

"BROTHER. WHAT ARE YOU TALKING ABOUT?"

"this human that is going to fall soon can control time. they have determination. they can die and come back to life. it doesn't matter. that is what i am trying to fix. this machine behind our house can go back in time. i have tried for so long to fix it. just give me some time. i will get it done."

"BROTHER. WHY HAVE YOU SAID NOTHING THIS WHOLE TIME? I, THE GREATE PAPYRUS SHALL HELP YOU SOLVE THIS PUZZLE."

"nah bro it is alright. i'm almost done anyways." Papyrus is always eager to help but he knows nothing about science or technology.

"WELL THEN. I SHALL HELP YOU BY MAKING THE BEST SPAGHETTI THIS WORLD HAS EVER KNOWN." With that he went to the kitchen.

After some more tinkering, and some terrible spaghetti, I have finally finished.

"BROTHER? ARE YOU ALRIGHT? DO YOU NEED MORE SPAGHETTI?"

"nah bro. i'm good."

"IF YOU SAY SO."

I was finally ready. I grabbed some burgers and fries, some extra ketchup, and was finally ready to go back to the past. I said my goodbyes and pulled the lever.

"BROTHER WAIT FOR MEeeee..." Then everything faded to black.

* * *

I woke up and looked around me. The machine was still there. My box full of food and ketchup was still in my hand. But the room was empty. I teleported to the ruins and knocked at the door.

"Who is there?" It was Toriel's voice.

"orange." It was the best joke I could come up with at the moment.

"Um... orange who?" She asked. She was definitely crying earlier.

"orange you glad to meet a new pal?" She giggled a bit.

"How can you make jokes when my son died yesterday? And my adopted child Chara was unwell for a week and died today as well." Dang in. Good job Sans. Well at least now I know how far to go in to the past.

"i'm sorry about that. i just travelled back in time and I didn't know when they died. i am here to fix that and prevent their death." She probably won't believe me but it won't matter.

"Are you serious? Who are you? What do you want?"

"it doesn't matter right now. but i am here to help. just tell me the place where your children were before they died and i will try to help them."

"I don't think you can do anything to help him. But if you are saying the truth then they were in the kings castle. If you can really go back in to the past then tell my past self that I hid the knives under the bookcase. That is something only I know."

"thank you toriel."

"How do you know my name? I don't recognize your voice."

"you will know in the future." I teleported away and inserted the time in my machine. Then I pulled the lever.

* * *

I was back at the basement. I went outside and looked around. Nothing unusual. I teleported to the kings castle and knocked at the door. My non existing heart was beating fast. I was actually really nervous. But at least I don't have a past version of myself to walk into. What could go wrong? The only monster that could possibly recognize me was Gaster. But Gaster was always in his lab.

The door opened and I saw Toriel.

"Hello. Pardon me but I do not recognize you. Who are you?"

"my name is sans. i know this might sound crazy but i am from the future and in the future both of your kids die. also your future self told me to tell you that you hid the knives under the bookcase. you said that it was something only you knew."

She stood there with a loss for words. Then she finally managed to say. "How did they die?"

"i don't know. but chara was unwell for a week. then they died and your son died on the same day. that is all you told me."

"But you could be lying"

I stoped time, teleported to the machine, got my ketchup bottle, then teleported back and resumed the time. I showed her the date the ketchup bottle was made.

"this bottle of ketchup was made yesterday by my time. but as you can see that is not the case for you." She took the bottle and looked at it carefully. Then turned it over and looked at it again.

"How?"

"i fixed a machine that was made by w.d. gaster. but he was split into two monsters. me and my brother. he is still alive in your time but soon he will fall into the core."

"Then we must warn him."

"no. if he doesn't fall into the core then i will never exist. if i never exist then i won't go into the past which means that no one will warn him. but that means that he will fall into the core. all that will cause a paradox which will destroy this timeline."

"What do you need?"

"i need to talk to your children. perhaps i can prevent their deaths."


	2. Chapter 2

**Sans' pov.**

"Kids. There is someone who wants to talk to you." Toriel said.

"hello kiddos." They were drawing something. Asriel was drawing a flower and Chara was drawing a heart.

"Ok I'll leave you lot alone for now. I need to talk to Asgore about something."

After she left the room an awkward silence filled the room. I wasn't sure what to do now. Should I approach the subject directly or not? How to approach it?

"hello. my name is sans. comic sans. and what are your names?" Nice and smooth Sans. Don't approach right away.

"Who are you?" Chara asked. She ( **They are a girl in this fan fiction. Because requests and stuff.)** looked a bit worried. But she wasn't at all what I was expecting. Calm and shy here. But she was violent in the future.

"i am a doctor. and a scientist." Nice cover up. Maybe it'll work.

"My name is Chara." She looked a bit intimidated. Was I really that scary? To be fair I am a skeleton. And humans aren't used to seeing skeletons without skin.

"Mine is Asriel. Chara is my sister."

"so how are you two doing? doing well? you seem like a friendly pair to me."

"Yeah. Talking. Sharing stories. Drawing a lot." Asriel talked freely. I guess I will get more info from him. It is only two weeks before they both die.

"so what happened with asgore. he didn't look so well."

Chara looked down and said "we accidentally used buttercups instead of cups of flowers in the pie we made. And buttercups are poisonous." That explains a lot. And as far as I can guess Chara fell ill probably from the buttercups. I wasn't prepared. I need to know how these two died. But there is only one monster who can tell me that. But he isn't in this time. I need to leave and go to my time.

I said my goodbyes and then left the room. I met Toriel on the way out and she allowed me to come back tomorrow. I left the castle and then teleported to my machine. I imputed my time and date and pulled the switch.

Finally I was home. Now where is that damn weed. But as I just got out of my machine I heard the answer to my question.

"So you can time travel. And what we're you doing in the past and why did you visit me and Chara? Let me guess. You came back because you wanted some info on why me and Chara died?" For a soulless murdered this flower was clever.

"yep that is the reason. so how did you die?"

"And why would I tell you?"

"because if you do then you won't be a flower. And chara would be alive."

This shocked Flowey.

"Why are you doing this?"

"not because i like you but because i'm sick of you."

"Fair enough. Well Chara had a plan to kill herself and let me take the soul. Then I was to go to the surface and kill some humans. Yet I refused. And died. I didn't know that the only answer back then was kill or be killed. I didn't want to kill and was, as expected, killed. There. Now you know."

"but you went along with the plan. and didn't follow it. why not say no in the first place?"

"I thought killing was going to be easy. But those people didn't what to be killed and I saw the fear in their eyes."

"thanks flowey. don't worry. you won't be a flower forever.

"Are you really going to do this?"

"yep."


	3. Chapter 3

**Sans's pov.**

I went to grillbys and got more ketchup. It was a long day and I had to make a plan on how to talk the kids out of their plan. It might take some time thought. Then again that is something I have lots of. Yet I felt like my little trip wasn't uneventful. Flowey was probably not the only one to remember. Toriel definitely was. I went to Toriel. As soon as I knocked I heard her respond.

"How could you. You went into the past and did nothing. You just talked. You didn't even say anything to the kids. You said you would be back tomorrow and you didn't come."

"toriel calm down. i didn't do anything yet because I had to go back to this time and get the info. i know how the kids died. i know what happened. that flower told be everything. that flower is asriel. But lots of experiments brought him back without a soul."

"What? But why didn't you come back?"

"i'm going to. but i need a plan. chara ate buttercups in order to die and let asriel take her soul. then he had to go to the surface and kill some humans. then he would take that souls and set everyone free. but asriel is not a killer. yet the humans still killed him."

"B-b-but why? Why did Chara want that?"

"i don't know yet. but i am going to find out. i'm going back to the past. see you later t. or should i say... 'sooner'.

I left and went for some food. Got myself burgers and fries. Lots of ketchup. And then I got back into the machine.

I got back into the past. Not much changed. Same room. I teleported to the castle. Got in. I decided to not mention the plan to Toriel. I need to talk to Chara first.

"Children. Mister Sans is here."

I talked to them for some time about their day, drawings, other things. After about 30 min I asked for Asriel to leave me and Chara alone.

After he left Chara turned around.

"Why have you come here? I know you are not from here. You are from far away. I know everyone my dad knows and he doesn't know you."

"kid. you might not believe me. but i am from the future."

Chara turned back to me and looked shocked.

"told ya. you won't believe it. but your plan to free all of monster kind will fail. you and asriel will both die."

"What? You are crazy. The plan can't fail. Prove it. That you are from the future. What happened to my soul? And what happened to Asriel?"

"asriel was resurrected..."

"So nothing..."

"into a soulless killer plant. he can't feel a thing and kills for fun. that is what you made your brother into. do you really want that for him?"

"Resurrected into a soulless plant? You got quite the imagination."

"HE ISN'T LYING YOU IDIOT. You got me killed. Thanks a lot for that."

Flowey was here? How? Did he follow me? But it might be for the best.

C: who the hell are you?

A/F: Oh right. I didn't introduce myself. How rude of me. Oh wait I just remembered. I DONT CARE ABOUT MANNERS. I AM DEAD BECAUSE OF YOU. YOUR PLAN FAILED. YOU GOT US KILLED. AND NOW I AM A GOD DAMN PLANT FOR THE REST OF MY STUPID LIFE. THANKS SO MUCH FOR THAT."

Chara looked really scared. Then again a screaming flower who was their dead brother is pretty terrifying.

C: prove it. Prove that you are my brother.

F: Why?

C: so I know that you are really my brother.

Flower puts on his creepy goat face on and sais in an equally creepy voice.

F: SinCE WheN Do yOU ThiNk a SOulLeSs pLAnT CaREs?

Chara was definitely scared now. She backed up and screamed for her mother.

Toriel came in and saw the flower.

T: Who the hell are you and why are you terrorizing my daughter?

F: Oh hello mom of the past. Didn't see you for a while. Well I kinda died and now IM A PLANT FOR THE REST OF MY LIFE. THANKS A LOT _SISTER._ YOU TOOK SUCH GREAT CARE OF ME.

T: I don't know what the hell you are but you are not my son. He would never hurt anyone.

F: Well that was true. But then me and Chara had this plan. Mostly their idea. They would kill themselves with buttercups. Then I would take their soul and kill some humans. But I refused at the last second and the humans killed me. I learned once and for all, It'S KiLl Or bE KillED.

T: that is not true. Chara couldn't have thought of that.

F: Oh really? Why don't we ask Chara who is currently present? Come on Chara. Tell your mom that I'm lying. That I have no soul because of other reasons. TeLl hEr ThAT YOu DINt GEt Me KillEd.

T: Chara?

C: H-h-how do you know of the plan? Only Asriel knows.

F: like I said I AM ASRIEL. But the dead, less kind more desensitized version. How does it feel to look at your brother but all twisted and demonic and know that you are the only person responsible for that?

I kept silence for most of this conversation. But I stood up because i felt my arm go numb. Then I saw that my arm wasn't even there.

T: Sans are you alright?

S: sorry toriel. but it looked like i don't have much time left here. neither does flowey. the future is changing and i am disappearing. but we will meet soon. in the future for me.

My whole body went limb. Then I felt myself falling into darkness.


	4. Chapter 4 finaly

**Sans's pov.**

Frisk is gonna be confused when she gets here. I am going to leave a message.

 _Hey kid. If you are reading this then don't be surprised that no one is here. Everyone left a while ago. After Chara didn't put her plan into action Asriel didn't die. Six more humans fell and none of them got killed. Asriel couldn't repeat the same process he once did without killing the humans since he no longer had determination to stop time. So I did it all instead. Now we are free and happy. Humanity saw that we monsters were capable of taking care of humans. We were accepted. Now if you wana meet us proceed out of the underground following this line. It'll lead you out of the underground. You might meet some monsters on the way out. Don't worry they won't fight. See yay kid. You might not remember anything but I still do._

 **THE END**


End file.
